CN102373999A - Method and apparatus for predicting peak temperature in a vehicle particulate filter - Google Patents

Abstract

A vehicle includes an internal combustion engine having an exhaust port, a regenerable particulate filter in fluid communication with the exhaust port, and a host machine which calculates a predicted peak temperature in the particulate filter. The host machine automatically executes a control action when the predicted peak temperature exceeds a calibrated threshold, thus preventing the peak temperature from being realized. A soot model may be used to estimate filter soot loads and corresponding burn rates, with the host machine extracting information from the soot model to calculate the predicted peak temperature. A system for use aboard the vehicle includes the particulate filter and host machine configured as noted above. A method for use aboard the vehicle includes calculating a predicted peak temperature in the particulate filter using the host machine, and automatically executing a control action when the predicted peak temperature exceeds a calibrated threshold.

Description

Estimate the method and apparatus of peak temperature in the vehicle particulate filter

Technical field

The present invention relates to be used for estimating the method and apparatus of the interior peak temperature of vehicle particulate filter in the vehicle exhaust stream.

Background technique

Particulate filter is designed to from the blast air of vehicle, remove the microscopic particulate in cigarette ash, ashes, metal and other suspended materials.As time goes on, accumulate in the substrate of particulate matter in filter.In order to prolong the life-span of this particulate filter, and further optimize the function of motor, with some filter design for can use heat optionally to regenerate.

Can be through directly with in the cylinder chamber of fuel injection engine or the filter exhaust gas stream upstream and light said fuel, thus can the temperature in the particulate filter temporarily be promoted between about 450 ℃ to 600 ℃.Can the peak value of delivery temperature combined use together such as palladium or the such suitable catalyst of platinum, wherein said catalyzer and heat one work, the particulate matter of any accumulation is resolved into the carbon soot of relative inertness via simple exothermic oxidation process.

Summary of the invention

The disclosed vehicle of this paper comprises motor, renewable particulate filter and main frame.This particulate filter receives blast air from exhaust opening of engine, in certain embodiments through being positioned at the oxidation catalyzer at its upper reaches.Main frame calculates at the expectation peak temperature that in said particulate filter, will reach under the current vehicles operation conditions, promptly under the situation that does not receive any control action.Main frame can be partly through with reference to one or more models with obtain the numerical value that needs and estimate this peak temperature, such as filter soot LOADING RATES and corresponding rate of combustion through estimating.

Main frame will be estimated peak temperature and compare through the threshold value of calibrating, and the record diagnosis code is to reflect its result.When the peak temperature of estimating surpassed threshold value, main frame can automatically perform engine control action or the action of other appropriate control.In the method as herein described of back, main frame can prevent that the peak temperature of estimating from really realizing, and protects the substrate of particulate filter not bear the peak value of temperature above the thermal boundary of crossing through test verification of filter thus.

A kind of system and method that on vehicle, uses also is provided.This system comprises above-mentioned particulate filter and main frame.Main frame calculates the expectation peak temperature in the particulate filter, and when this expectation peak temperature surpasses the threshold value of warp calibration, automatically performs control action.

Can this method be embodied as the algorithm of being carried out by main frame.This method comprises uses main frame to estimate peak temperature in the particulate filter to calculate through using a model, and said model is such as being cigarette ash model and/or thermal model, and it provides the cigarette ash load of estimating, particulate filter quality and corresponding rate of combustion.This method also can comprise using on demand estimates that peak temperature comes ato unit management and control action or the action of other appropriate control.

Easily understand above-mentioned feature and advantage of the present invention and other feature and advantage in the detailed description that the better model to embodiment of the present invention that combines accompanying drawing to carry out is hereinafter made.

Description of drawings

But Fig. 1 is the schematic representation of vehicle that comprises the particulate filter of explosive motor and thermal regeneration; With

Fig. 2 is a method flow diagram of having described the peak temperature that is used for estimating the particulate filter that on the vehicle shown in Fig. 1, uses.

The practical implementation method

Referring to accompanying drawing, wherein in these a few width of cloth accompanying drawings identical reference character corresponding identical or similar member, schematically show vehicle 10 among Fig. 1.Vehicle 10 comprises main frame (host machine) 40 and algorithm 100; This algorithm 100 is optionally carried out by main frame 40; To calculate the expectation peak temperature in oxidation catalyzer (OC:oxidation catalyst) system 13 that vehicle 10 is loaded with under the current vehicle operation conditions; And preventing that after this this expectation peak temperature from really realizing, with the some parts of protecting this OC system bearing temperature peak value not.Followingly algorithm 100 is carried out more detailed description with reference to Fig. 2.

Vehicle 10 comprises such as DENG or such explosive motor 12, OC system 13 and the transmission device 14 of direct injection spark ignition engine.Motor 12 will be by the fuel that takes out in the fuel tank 18 16 burnings.In a possible embodiment, this fuel 16 is diesel oil, and OC system 13 is diesel oil oxidation catalyst converter (DOC:diesel oxidation catalyst) systems, but also can use the fuel of other types according to the design of motor 12.

Throttle (throttle) 20 optionally makes fuel 16 and AIR MIXTURES get into motor 12 as required.The burning of fuel 16 produces blast air 22, in case this blast air filters through OC system 13 then finally drains in the ambient atmosphere.The energy that is discharged by the burning of fuel 16 produces moment of torsion on the input block 24 of transmission device 14.Torque transfer to the output block 26 that this transmission device 14 will be transmitted by motor 12 subsequently with via one group of wheel, 28 propelled vehicles 10, only shows a described wheel from simple and clear purpose in Fig. 1.

OC system 13 is in blast air 22 cleaning and regulate said blast air 22 when the relief opening (one or more) 17 of motor 12 is flowed through the vent systems of vehicle.This OC system 13 can comprise oxidation catalyzer 30 and particulate filter 34.According to a possible embodiment, when fuel 16 is diesel oil, can this particulate filter 34 be configured to diesel particulate filter (DPF:diesel particulate filter).Can optional SCR (SCR:selective catalytic reduction) equipment be arranged between oxidation catalyzer 30 and the particulate filter 34; To use active catalytic device (active catalyst) to convert nitrogen oxide (NOx) gas to water and the such by-product of nitrogen, the active catalytic device for example is ceramic brick or ceramic honeycomb, platy structure or any other suitable design.

Irrelevant with the composition of fuel 16, particulate filter 34 is to use heat optionally to regenerate.The regeneration of particulate filter 34 can be active or passive type.Will be understood that the extra control action that passive type regeneration need not be used to regenerate in the art.On the contrary, particulate filter 34 is installed in the position of baffler, and particulate matter is trapped in the substrate in the filter when idle running or low power run.Along with delivery temperature rises, the material that captures in the particulate filter 34 is deflated stream 22 burning or oxidations.On the contrary, active regeneration uses external heat source with auxiliary regeneration, also needs extra controlling method.

Still with reference to Fig. 1, particulate filter 34 comprises substrate 35, and it can be processed by pottery, wire netting, ball shape aluminium oxide or any other temperature and the suitable material (one or more) of purposes.Along with the engine exhaust stream temperature raises, in the substrate 35 of particulate filter 34 or the material of interior capture be deflated stream 22 burning or oxidations, as stated.Some possible regeneration method comprise and use alkali metal or precious metal coating filter base 35, reduce the required temperature of particulate matter oxidation thus, install such as the such catalyst converter of oxidation catalyzer 30 at the particulate filter upper reaches, use the catalyzer that fuel contains (fuel-borne catalyst: fuel oil additive) burn temperature (burn-off temperature) etc. with what reduce the particulate that captures.

In using the embodiment of oxidation catalyzer 30, can particulate filter 34 be connected to oxidation catalyzer 30 or process with said oxidation catalyzer integral body.In other embodiments, can fuel injection device 36 be set to be communicated with main frame 40 fluids, and via control signal 15 controls.When through main frame 40 decisions, the fuel 16 that fuel injection device 36 optionally will take out from fuel tank 18 injects oxidation catalyzer 30 or engine cylinder (not shown).Fuel 16 so that the controlled way burning is injected to produce the heat of enough levels, makes particulate filter 34 regeneration.

Yet the temperature in the particulate filter 34 can reach the level that surpasses through the threshold value of calibration every now and then.Therefore, also can main frame 40 be configured to the expectation peak temperature in serviceability temperature and the cigarette ash Model Calculation particulate filter 34, and take any necessary control action really to realize in advance to prevent this expectation peak temperature.

Can main frame 40 be configured to the digital computer as vehicle control device; And/or proportional-integral-differential (PID) controller equiment, said equipment has microprocessor or central processing unit (CPU), ROM (read-only memory) (ROM), random-access memory (ram), electronics erasable type programmable read only memory (EEPROM), high-frequency clock, mould-number (A/D) and/or number-Mo (D/A) circuit and any required input/output circuitry and relevant equipment and any required Signal Regulation and/or signal buffer circuit.Algorithm 100 can be by main frame 40 storages or visit easily, to provide hereinafter with reference to the described function of Fig. 2 with any required Reference standard (reference calibration).

Main frame 40 is from being arranged on the OC system 13 interior diverse locations, being used for measuring a plurality of sensors 42 reception signals 11 such as the exhaust quality of temperature, pressure, oxygen level etc., and said position comprises direct upstream and downstream at oxidation catalyzer 30 and particulate filter 34.Main frame 40 is also communicated by letter with motor 12, shows the feedback signal 44 of current vehicle operation conditions with reception, such as Engine torque of throttle position, transmitter rotating speed, acceleration device pedal position, fuel quantity, requirement etc.

Can be by main frame 40 execution algorithms 100, to calculate under the current vehicle operation conditions expectation peak temperature in the particulate filter 34.When carrying out said expectation, but main frame 40 reference temperature models 50 and cigarette ash model 60, with the information after acquisition is calibrated as required from each model.The information that main frame 40 uses the intrabasement specific energy (rate of energy) that inputs to particulate filter 34 and discharges and transfer to energy in the substrate (i.e. oxidation through convection current, hydrocarbon and carbon soot etc.) and come self model 50 and 60, and calculate the interior expectation peak temperature of particulate filter 34 subsequently.

Such method depends on temperature and cigarette ash model 50,60 prediction accuracy separately, and does not depend on the inlet temperature through measuring of using the particulate filter 34 in the traditional mode close-loop feedback control process.Main frame 40 will be estimated peak temperature and compare through the threshold value of calibrating.Surpass this threshold value if estimate peak temperature, then main frame can prevent that in every way this expectation peak temperature from really realizing via one or more control actions.

Referring to Fig. 2, the algorithm of being carried out by main frame 40 100 calculates under the current vehicle operation conditions, the expectation peak temperature in the particulate filter 34, and it is abbreviated as T _{PF, PEAK},, reduce the possibility that this expectation peak temperature is really realized thus so that main frame 40 can be asked the appropriate control action in advance.

Algorithm 100 is begun by step 102.In this step, use formula to calculate the energy input rate

of injecting OC system 13 by main frame 40

${\stackrel{\·}{Q}}_{\mathrm{IN}}=\frac{T_g}{C_g{\stackrel{\·}{M}}_g},$

T wherein _gBe the delivery temperature of measuring, C _gBe the specific heat of known exhaust 22, and

It is the mass flowrate (mass flow rate) of exhaust 22.Algorithm 100 gets into step 104 subsequently.

In step 104; For example through serviceability temperature model 50; The net energy output rating

that main frame 40 is obtained the blast air 22 that leaves particulate filter 34 value with subsequently changes into the output temperature value; Promptly; Multiply by at this moment, the energy balance formula that

can be basic with this is used for confirming shifting with particulate filter 34 relevant total energies.

That is, can use the information that is obtained by temperature model 50 to confirm to shift with substrate 35 relevant energy by main frame 40, this moment, temperature model uses formula to replenish:

E _PF，TOTAL＝(E _PF，OUT-E _PF，IN)+E _SOOT，

Wherein can confirm E via formula _SOOT,

${\mathrm{Hv}}_{\mathrm{CARBON}}({\stackrel{\·}{R}}_{O2}-{\stackrel{\·}{R}}_{\mathrm{NO}2}),$

Hv wherein _CARBONBe the heat value of the particulate matter in the particulate filter 34, and

The cigarette ash quality consumption rate that representative realizes through the oxidation in the particulate filter.Algorithm 100 gets into step 106 subsequently.

In step 106, calculate the expectation peak temperature by main frame 40.Main frame 40 addressable models 50 and 60, and obtaining such as rate of combustion and the such information of specific heat of combustion, and as follows use the energy balance formula that obtains by model to calculate expectation peak value, i.e. T _{PF, PEAK}:

$T_{\mathrm{PF},\mathrm{PEAK}}=T_0+\frac{\left(E_{\mathrm{PF},\mathrm{TOTAL}}\right)\left(t_{\mathrm{ZSOOT}}\right)}{\left(C_{\mathrm{pPF}}\right)\left(M_{\mathrm{PF}}\right)},$

T wherein ₀Be the Current Temperatures of particulate filter 34, C _PPFBe the specific heat of substrate 35, and M _PFIt is the quality of substrate 35.Value t _ZSOOTBe by cigarette ash model 60 obtain in particulate filter 34, do not have cigarette ash remaining basically the time remaining time, be to use formula to calculate and be stored in the value in the cigarette ash model in advance:

$t_{\mathrm{zSOOT}}=\frac{M_{\mathrm{SOOT}}}{{\mathrm{dM}}_{\mathrm{SOOT}}/\mathrm{dT}}=\frac{M_{\mathrm{SOOT}}}{{\mathrm{\η}}_{f}P{\stackrel{\·}{M}}_{\mathrm{eng},\mathrm{out}}-({\stackrel{\·}{R}}_{O2}-{\stackrel{\·}{R}}_{\mathrm{NO}2})}$

Can estimate from cigarette ash model 60, to obtain information by main frame 40 in the peak temperature process in the calculating that is described below.On occur before this in two formula, M _SOOTBe the quality of cigarette ash, η _fBe the filter efficiency of particulate filter 34, and

Be the cumulative percentage of interior cigarette ash of particulate filter or particulate matter, i.e. PM.

Character through knowing substrate 35 also is stored in said value known or calibration in the temperature model 50, and the above-mentioned formula that uses the front to occur is then confirmed at the time t through calculating _ZSOOTOn the expectation peak temperature T of particulate filter 34 _{PF, PEAK}

In step 108, main frame 40 will be estimated peak temperature (T _{PF, PEAK}) and compare through the threshold value of calculating, and its result's of record reflection sign (flag), for example when not surpassing threshold value, diagnostic code or sign are set at 0, and when surpassing threshold value, different diagnostic codes or sign are set at 1.After having write down result relatively, algorithm 100 gets into step 110.

In step 110, when estimating peak temperature (T _{PF, PEAK}) when surpassing the threshold value of warp calibration, main frame 40 can be carried out control action in advance.As used herein, control action in advance refers to as far back as estimating peak temperature (T _{PF, PEAK}) really realize before the just control action of enforcement, thereby preventing the temperature in the particulate filter 34, control action reaches the level of expectation.Possible control action in advance for example is but is not subject to such as reducing O in the blast air ₂Level, optionally cylinder deactivation, reduce such motor management and control action such as hydrocarbon injection rate.

Use aforesaid algorithm 100 and main frame 40, can only get into protected mode where necessary, with protection particulate filter 34.Can be via under the expectation operation conditions, given vehicle 10 being tested and being verified and definite in advance calibration threshold value, to optimize the degree of accuracy of cigarette ash model 60, temperature model 50 and algorithm 100.That is,, limit the thermal boundary (thermal boundary) of particulate filter 34 exactly, and the test of experience strictness subsequently is to obtain the understanding to the statistical distribution of different failure modes, like the surface check or the internal crack of substrate 35 in the design phase.

Means such as finite element analysis capable of using obtain the understanding of failure probability in working life of particulate filter 34 under given temperature distribution.Can implement the robustness of some steps in the design phase subsequently, and optimize thermal boundary, and this method is executed these borders of clearly setting with the increase substrate material.

Although carried out detailed description to carrying out better model of the present invention, those skilled in the art can learn the many replacement designs and the embodiment that are used for embodiment of the present invention in the scope of appended claim.

Claims (10)

1. vehicle, it comprises:

Explosive motor, it has relief opening;

Particulate filter, it is communicated with said engine fluid via said relief opening, and wherein, said particulate filter can use heat and regenerate; With

Main frame can be used for calculating the expectation peak temperature in the said particulate filter, and when said expectation peak temperature surpasses the threshold value of warp calibration, automatically performs control action;

Wherein, the enforcement of said control action prevents that said peak temperature from really realizing.

2. vehicle as claimed in claim 1, this vehicle comprise the model that filter soot load and corresponding rate of combustion are estimated, wherein, said main frame is acquired information from said cigarette ash model, and uses the said expectation peak temperature of said information calculations.

3. vehicle as claimed in claim 1, wherein, said main frame automatically performs the motor management and control action as said control action.

4. vehicle as claimed in claim 1; Also comprise the fuel injection device; Said choice of equipment property ground injects said blast air with fuel; Promoting the regeneration temperature of said particulate filter, wherein said control action comprises through in the running of said fuel injection device, starting feedback control and reduces regeneration temperature.

5. vehicle as claimed in claim 1, wherein, said main frame produces the diagnostic code as at least a portion of said control action, and the value of said diagnostic code is corresponding to the value of the said expectation peak temperature relevant with the threshold value of warp calibration.

6. method of on vehicle, using, this vehicle have explosive motor, can be with the particulate filter and the main frame of heat regeneration, said method comprises:

Use said main frame to calculate the expectation peak temperature in the said particulate filter; With

, said expectation peak temperature automatically performs control action when surpassing the threshold value of warp calibration;

Therefore wherein, the execution of said control action prevents that said peak temperature from really realizing.

7. method as claimed in claim 6, wherein, said vehicle comprises the model that filter soot load and corresponding rate of combustion are estimated, said method also comprises:

Acquired information from said cigarette ash model; With

Use the said expectation peak temperature of said information calculations.

8. method as claimed in claim 6, it also comprises:

Automatically perform motor management and control action as said control action.

9. method as claimed in claim 6, said vehicle also comprises the fuel injection device, and said choice of equipment property ground injects said blast air with fuel, and to promote the regeneration temperature of said particulate filter, said method also comprises:

As at least a portion of said control action, reduce said regeneration temperature through in the running of said fuel injection device, starting feedback control.

10. method as claimed in claim 6 also comprises the generation diagnostic code, and the value that said diagnostic code has is corresponding to the value of the said expectation peak temperature relevant with the threshold value of said warp calibration.

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